630 lines
19 KiB
JavaScript
630 lines
19 KiB
JavaScript
var hasOwnProperty = Object.prototype.hasOwnProperty;
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var matchGraph = require('./match-graph');
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var MATCH = matchGraph.MATCH;
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var MISMATCH = matchGraph.MISMATCH;
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var DISALLOW_EMPTY = matchGraph.DISALLOW_EMPTY;
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var TYPE = require('../tokenizer/const').TYPE;
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var STUB = 0;
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var TOKEN = 1;
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var OPEN_SYNTAX = 2;
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var CLOSE_SYNTAX = 3;
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var EXIT_REASON_MATCH = 'Match';
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var EXIT_REASON_MISMATCH = 'Mismatch';
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var EXIT_REASON_ITERATION_LIMIT = 'Maximum iteration number exceeded (please fill an issue on https://github.com/csstree/csstree/issues)';
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var ITERATION_LIMIT = 15000;
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var totalIterationCount = 0;
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function reverseList(list) {
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var prev = null;
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var next = null;
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var item = list;
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while (item !== null) {
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next = item.prev;
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item.prev = prev;
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prev = item;
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item = next;
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}
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return prev;
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}
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function areStringsEqualCaseInsensitive(testStr, referenceStr) {
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if (testStr.length !== referenceStr.length) {
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return false;
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}
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for (var i = 0; i < testStr.length; i++) {
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var testCode = testStr.charCodeAt(i);
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var referenceCode = referenceStr.charCodeAt(i);
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// testCode.toLowerCase() for U+0041 LATIN CAPITAL LETTER A (A) .. U+005A LATIN CAPITAL LETTER Z (Z).
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if (testCode >= 0x0041 && testCode <= 0x005A) {
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testCode = testCode | 32;
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}
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if (testCode !== referenceCode) {
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return false;
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}
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}
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return true;
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}
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function isCommaContextStart(token) {
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if (token === null) {
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return true;
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}
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return (
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token.type === TYPE.Comma ||
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token.type === TYPE.Function ||
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token.type === TYPE.LeftParenthesis ||
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token.type === TYPE.LeftSquareBracket ||
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token.type === TYPE.LeftCurlyBracket ||
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token.type === TYPE.Delim
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);
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}
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function isCommaContextEnd(token) {
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if (token === null) {
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return true;
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}
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return (
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token.type === TYPE.RightParenthesis ||
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token.type === TYPE.RightSquareBracket ||
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token.type === TYPE.RightCurlyBracket ||
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token.type === TYPE.Delim
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);
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}
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function internalMatch(tokens, state, syntaxes) {
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function moveToNextToken() {
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do {
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tokenIndex++;
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token = tokenIndex < tokens.length ? tokens[tokenIndex] : null;
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} while (token !== null && (token.type === TYPE.WhiteSpace || token.type === TYPE.Comment));
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}
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function getNextToken(offset) {
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var nextIndex = tokenIndex + offset;
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return nextIndex < tokens.length ? tokens[nextIndex] : null;
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}
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function stateSnapshotFromSyntax(nextState, prev) {
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return {
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nextState: nextState,
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matchStack: matchStack,
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syntaxStack: syntaxStack,
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thenStack: thenStack,
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tokenIndex: tokenIndex,
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prev: prev
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};
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}
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function pushThenStack(nextState) {
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thenStack = {
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nextState: nextState,
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matchStack: matchStack,
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syntaxStack: syntaxStack,
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prev: thenStack
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};
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}
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function pushElseStack(nextState) {
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elseStack = stateSnapshotFromSyntax(nextState, elseStack);
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}
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function addTokenToMatch() {
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matchStack = {
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type: TOKEN,
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syntax: state.syntax,
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token: token,
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prev: matchStack
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};
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moveToNextToken();
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syntaxStash = null;
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if (tokenIndex > longestMatch) {
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longestMatch = tokenIndex;
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}
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}
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function openSyntax() {
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syntaxStack = {
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syntax: state.syntax,
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opts: state.syntax.opts || (syntaxStack !== null && syntaxStack.opts) || null,
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prev: syntaxStack
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};
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matchStack = {
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type: OPEN_SYNTAX,
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syntax: state.syntax,
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token: matchStack.token,
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prev: matchStack
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};
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}
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function closeSyntax() {
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if (matchStack.type === OPEN_SYNTAX) {
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matchStack = matchStack.prev;
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} else {
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matchStack = {
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type: CLOSE_SYNTAX,
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syntax: syntaxStack.syntax,
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token: matchStack.token,
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prev: matchStack
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};
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}
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syntaxStack = syntaxStack.prev;
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}
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var syntaxStack = null;
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var thenStack = null;
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var elseStack = null;
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// null – stashing allowed, nothing stashed
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// false – stashing disabled, nothing stashed
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// anithing else – fail stashable syntaxes, some syntax stashed
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var syntaxStash = null;
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var iterationCount = 0; // count iterations and prevent infinite loop
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var exitReason = null;
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var token = null;
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var tokenIndex = -1;
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var longestMatch = 0;
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var matchStack = {
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type: STUB,
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syntax: null,
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token: null,
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prev: null
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};
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moveToNextToken();
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while (exitReason === null && ++iterationCount < ITERATION_LIMIT) {
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// function mapList(list, fn) {
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// var result = [];
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// while (list) {
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// result.unshift(fn(list));
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// list = list.prev;
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// }
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// return result;
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// }
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// console.log('--\n',
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// '#' + iterationCount,
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// require('util').inspect({
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// match: mapList(matchStack, x => x.type === TOKEN ? x.token && x.token.value : x.syntax ? ({ [OPEN_SYNTAX]: '<', [CLOSE_SYNTAX]: '</' }[x.type] || x.type) + '!' + x.syntax.name : null),
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// token: token && token.value,
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// tokenIndex,
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// syntax: syntax.type + (syntax.id ? ' #' + syntax.id : '')
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// }, { depth: null })
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// );
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switch (state.type) {
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case 'Match':
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if (thenStack === null) {
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// turn to MISMATCH when some tokens left unmatched
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if (token !== null) {
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// doesn't mismatch if just one token left and it's an IE hack
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if (tokenIndex !== tokens.length - 1 || (token.value !== '\\0' && token.value !== '\\9')) {
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state = MISMATCH;
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break;
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}
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}
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// break the main loop, return a result - MATCH
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exitReason = EXIT_REASON_MATCH;
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break;
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}
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// go to next syntax (`then` branch)
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state = thenStack.nextState;
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// check match is not empty
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if (state === DISALLOW_EMPTY) {
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if (thenStack.matchStack === matchStack) {
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state = MISMATCH;
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break;
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} else {
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state = MATCH;
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}
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}
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// close syntax if needed
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while (thenStack.syntaxStack !== syntaxStack) {
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closeSyntax();
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}
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// pop stack
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thenStack = thenStack.prev;
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break;
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case 'Mismatch':
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// when some syntax is stashed
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if (syntaxStash !== null && syntaxStash !== false) {
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// there is no else branches or a branch reduce match stack
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if (elseStack === null || tokenIndex > elseStack.tokenIndex) {
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// restore state from the stash
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elseStack = syntaxStash;
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syntaxStash = false; // disable stashing
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}
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} else if (elseStack === null) {
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// no else branches -> break the main loop
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// return a result - MISMATCH
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exitReason = EXIT_REASON_MISMATCH;
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break;
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}
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// go to next syntax (`else` branch)
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state = elseStack.nextState;
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// restore all the rest stack states
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thenStack = elseStack.thenStack;
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syntaxStack = elseStack.syntaxStack;
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matchStack = elseStack.matchStack;
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tokenIndex = elseStack.tokenIndex;
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token = tokenIndex < tokens.length ? tokens[tokenIndex] : null;
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// pop stack
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elseStack = elseStack.prev;
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break;
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case 'MatchGraph':
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state = state.match;
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break;
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case 'If':
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// IMPORTANT: else stack push must go first,
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// since it stores the state of thenStack before changes
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if (state.else !== MISMATCH) {
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pushElseStack(state.else);
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}
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if (state.then !== MATCH) {
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pushThenStack(state.then);
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}
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state = state.match;
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break;
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case 'MatchOnce':
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state = {
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type: 'MatchOnceBuffer',
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syntax: state,
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index: 0,
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mask: 0
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};
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break;
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case 'MatchOnceBuffer':
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var terms = state.syntax.terms;
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if (state.index === terms.length) {
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// no matches at all or it's required all terms to be matched
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if (state.mask === 0 || state.syntax.all) {
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state = MISMATCH;
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break;
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}
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// a partial match is ok
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state = MATCH;
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break;
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}
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// all terms are matched
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if (state.mask === (1 << terms.length) - 1) {
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state = MATCH;
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break;
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}
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for (; state.index < terms.length; state.index++) {
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var matchFlag = 1 << state.index;
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if ((state.mask & matchFlag) === 0) {
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// IMPORTANT: else stack push must go first,
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// since it stores the state of thenStack before changes
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pushElseStack(state);
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pushThenStack({
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type: 'AddMatchOnce',
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syntax: state.syntax,
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mask: state.mask | matchFlag
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});
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// match
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state = terms[state.index++];
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break;
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}
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}
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break;
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case 'AddMatchOnce':
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state = {
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type: 'MatchOnceBuffer',
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syntax: state.syntax,
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index: 0,
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mask: state.mask
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};
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break;
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case 'Enum':
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if (token !== null) {
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var name = token.value.toLowerCase();
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// drop \0 and \9 hack from keyword name
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if (name.indexOf('\\') !== -1) {
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name = name.replace(/\\[09].*$/, '');
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}
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if (hasOwnProperty.call(state.map, name)) {
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state = state.map[name];
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break;
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}
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}
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state = MISMATCH;
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break;
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case 'Generic':
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var opts = syntaxStack !== null ? syntaxStack.opts : null;
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var lastTokenIndex = tokenIndex + Math.floor(state.fn(token, getNextToken, opts));
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if (!isNaN(lastTokenIndex) && lastTokenIndex > tokenIndex) {
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while (tokenIndex < lastTokenIndex) {
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addTokenToMatch();
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}
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state = MATCH;
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} else {
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state = MISMATCH;
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}
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break;
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case 'Type':
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case 'Property':
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var syntaxDict = state.type === 'Type' ? 'types' : 'properties';
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var dictSyntax = hasOwnProperty.call(syntaxes, syntaxDict) ? syntaxes[syntaxDict][state.name] : null;
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if (!dictSyntax || !dictSyntax.match) {
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throw new Error(
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'Bad syntax reference: ' +
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(state.type === 'Type'
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? '<' + state.name + '>'
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: '<\'' + state.name + '\'>')
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);
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}
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// stash a syntax for types with low priority
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if (syntaxStash !== false && token !== null && state.type === 'Type') {
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var lowPriorityMatching =
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// https://drafts.csswg.org/css-values-4/#custom-idents
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// When parsing positionally-ambiguous keywords in a property value, a <custom-ident> production
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// can only claim the keyword if no other unfulfilled production can claim it.
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(state.name === 'custom-ident' && token.type === TYPE.Ident) ||
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// https://drafts.csswg.org/css-values-4/#lengths
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// ... if a `0` could be parsed as either a <number> or a <length> in a property (such as line-height),
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// it must parse as a <number>
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(state.name === 'length' && token.value === '0');
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if (lowPriorityMatching) {
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if (syntaxStash === null) {
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syntaxStash = stateSnapshotFromSyntax(state, elseStack);
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}
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state = MISMATCH;
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break;
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}
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}
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openSyntax();
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state = dictSyntax.match;
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break;
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case 'Keyword':
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var name = state.name;
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if (token !== null) {
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var keywordName = token.value;
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// drop \0 and \9 hack from keyword name
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if (keywordName.indexOf('\\') !== -1) {
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keywordName = keywordName.replace(/\\[09].*$/, '');
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}
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if (areStringsEqualCaseInsensitive(keywordName, name)) {
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addTokenToMatch();
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state = MATCH;
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break;
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}
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}
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state = MISMATCH;
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break;
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case 'AtKeyword':
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case 'Function':
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if (token !== null && areStringsEqualCaseInsensitive(token.value, state.name)) {
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addTokenToMatch();
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state = MATCH;
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break;
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}
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state = MISMATCH;
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break;
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case 'Token':
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if (token !== null && token.value === state.value) {
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addTokenToMatch();
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state = MATCH;
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break;
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}
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state = MISMATCH;
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break;
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case 'Comma':
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if (token !== null && token.type === TYPE.Comma) {
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if (isCommaContextStart(matchStack.token)) {
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state = MISMATCH;
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} else {
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addTokenToMatch();
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state = isCommaContextEnd(token) ? MISMATCH : MATCH;
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}
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} else {
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state = isCommaContextStart(matchStack.token) || isCommaContextEnd(token) ? MATCH : MISMATCH;
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}
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break;
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case 'String':
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var string = '';
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for (var lastTokenIndex = tokenIndex; lastTokenIndex < tokens.length && string.length < state.value.length; lastTokenIndex++) {
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string += tokens[lastTokenIndex].value;
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}
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if (areStringsEqualCaseInsensitive(string, state.value)) {
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while (tokenIndex < lastTokenIndex) {
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addTokenToMatch();
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}
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state = MATCH;
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} else {
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state = MISMATCH;
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}
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break;
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default:
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throw new Error('Unknown node type: ' + state.type);
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}
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}
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totalIterationCount += iterationCount;
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switch (exitReason) {
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case null:
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console.warn('[csstree-match] BREAK after ' + ITERATION_LIMIT + ' iterations');
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exitReason = EXIT_REASON_ITERATION_LIMIT;
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matchStack = null;
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break;
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case EXIT_REASON_MATCH:
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while (syntaxStack !== null) {
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closeSyntax();
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}
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break;
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default:
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matchStack = null;
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}
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return {
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tokens: tokens,
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reason: exitReason,
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iterations: iterationCount,
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match: matchStack,
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longestMatch: longestMatch
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};
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}
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function matchAsList(tokens, matchGraph, syntaxes) {
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var matchResult = internalMatch(tokens, matchGraph, syntaxes || {});
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if (matchResult.match !== null) {
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var item = reverseList(matchResult.match).prev;
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matchResult.match = [];
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while (item !== null) {
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switch (item.type) {
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case STUB:
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break;
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case OPEN_SYNTAX:
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case CLOSE_SYNTAX:
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matchResult.match.push({
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type: item.type,
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syntax: item.syntax
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});
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break;
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default:
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matchResult.match.push({
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token: item.token.value,
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node: item.token.node
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});
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break;
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}
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item = item.prev;
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}
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}
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return matchResult;
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}
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function matchAsTree(tokens, matchGraph, syntaxes) {
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var matchResult = internalMatch(tokens, matchGraph, syntaxes || {});
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if (matchResult.match === null) {
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return matchResult;
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}
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var item = matchResult.match;
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var host = matchResult.match = {
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syntax: matchGraph.syntax || null,
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match: []
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};
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var hostStack = [host];
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// revert a list and start with 2nd item since 1st is a stub item
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item = reverseList(item).prev;
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// build a tree
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while (item !== null) {
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switch (item.type) {
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case OPEN_SYNTAX:
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host.match.push(host = {
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syntax: item.syntax,
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match: []
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});
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hostStack.push(host);
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break;
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case CLOSE_SYNTAX:
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||
hostStack.pop();
|
||
host = hostStack[hostStack.length - 1];
|
||
break;
|
||
|
||
default:
|
||
host.match.push({
|
||
syntax: item.syntax || null,
|
||
token: item.token.value,
|
||
node: item.token.node
|
||
});
|
||
}
|
||
|
||
item = item.prev;
|
||
}
|
||
|
||
return matchResult;
|
||
}
|
||
|
||
module.exports = {
|
||
matchAsList: matchAsList,
|
||
matchAsTree: matchAsTree,
|
||
getTotalIterationCount: function() {
|
||
return totalIterationCount;
|
||
}
|
||
};
|